Re: [PATCH 4/4] samples/bpf: Enable powerpc support

[Alexei Starovoitov]

On 4/1/16 7:41 AM, Naveen N. Rao wrote:
> On 2016/03/31 10:52AM, Alexei Starovoitov wrote:
> > On 3/31/16 4:25 AM, Naveen N. Rao wrote:
> > ...
> > > +
> > > +#ifdef __powerpc__
> > > +#define BPF_KPROBE_READ_RET_IP(ip, ctx)		{ (ip) = (ctx)->link; }
> > > +#define BPF_KRETPROBE_READ_RET_IP(ip, ctx)	BPF_KPROBE_READ_RET_IP(ip, ctx)
> > > +#else
> > > +#define BPF_KPROBE_READ_RET_IP(ip, ctx)						\
> > > +		bpf_probe_read(&(ip), sizeof(ip), (void *)PT_REGS_RET(ctx))
> > > +#define BPF_KRETPROBE_READ_RET_IP(ip, ctx)					\
> > > +		bpf_probe_read(&(ip), sizeof(ip),				\
> > > +				(void *)(PT_REGS_FP(ctx) + sizeof(ip)))
> >
> > makes sense, but please use ({ }) gcc extension instead of {} and
> > open call to make sure that macro body is scoped.
>
> To be sure I understand this right, do you mean something like this?
>
> +
> +#ifdef __powerpc__
> +#define BPF_KPROBE_READ_RET_IP(ip, ctx)                ({ (ip) = (ctx)->link; })
> +#define BPF_KRETPROBE_READ_RET_IP              BPF_KPROBE_READ_RET_IP
> +#else
> +#define BPF_KPROBE_READ_RET_IP(ip, ctx)                ({                              \
> +               bpf_probe_read(&(ip), sizeof(ip), (void *)PT_REGS_RET(ctx)); })
> +#define BPF_KRETPROBE_READ_RET_IP(ip, ctx)     ({                              \
> +               bpf_probe_read(&(ip), sizeof(ip),                               \
> +                               (void *)(PT_REGS_FP(ctx) + sizeof(ip))); })
> +#endif

yes. Thanks!